This invention relates to a conveyor, in particular one whose carrying surface is formed by rollers mounted for free rotation and extending transversely to a direction of transport between two endless side chains adapted to be passed over return and drive wheels, the side chains pulling the rollers through the transport track and being of the type with interengaging parts lying in planes substantially perpendicular to each other, said parts allowing a temporary shortening of a chain by temporarily sliding one into another for traversing bends.
In a similar conveyor disclosed is British patent application No. 2,084,103, articles resting on the bearing rollers are carried along by the travelling conveyor or as long as the articles do not meet an obstacle, at least a resistance of any significance. As soon as this is the case, e.g. when the articles are not discharged from the conveyor or are discharged at a lower speed than that at which they are placed on the conveyor, jamming occurs at the discharge end, whereby the rollers start rotating, with the conveyor rolling underneath the articles. This arrangement prevents wear to the underside of the articles or to the conveyor.
As the rollers in the prior conveyor are constructed as tubes extending the full width of the transporting surface and being supported exclusively at their end portions on stubs projecting from the respective side chains, wear on the bottom of a relatively large article, such as a box, which is at a standstill in a corner zone, cannot be avoided. For the speed at which the outside bend end of each roller is displaced underneath the bottom of the article is higher than the speed of the inside bend end. At best, the rotation speed of the rollers will be determined by the speed of one end of the rollers rolling over the bottom of the article and the other roller end will slip over said bottom, thereby causing wear at that location. The friction occurring thereby, however, will retain said roller end relative to the other rolling end, so that the rollers will be thrown out of alignment with the bearing stubs of the side chains and can no longer rotate. The object contemplated with the prior conveyor, i.e. to enable the carrying surface to move underneath stationary articles without friction, is therefore not achieved with articles having a large bottom surface.